Here, he talks about his most recent feat: swimming one kilometer (nearly 20 minutes) in minus 1.8 degrees Celsius water at the North Pole in order to raise awareness of the melting polar ice cap and rising water levels. For every one hour he spent training in cold water, he spent four hours in “mind training” — visualizing himself at every phase of the swim and willing his brain to raise his core body temperature.

If you only have a few minutes and can’t watch all 19, I recommend dropping in at the 10:25 mark to watch a short film about his journey. It’s quite moving.